Simon, the son of Mundhir, was a native of Habsnas in Tur Abdin. He studied and became a monk at the Monastery of Qartamin around 657. In 682 he was ordained a priest and then the abbot of the same monastery. He is credited with building many churches and monasteries in Tur Abdin, which he also provided with large religious endowments. Among these were large tracts of vineyards and olive trees which he planted himself; hence, his nickname the Zaytuni (the Man of Olives). He was also helped in carrying out his work by a treasure he found hidden in a cave, which he devoted to charitable purposes. In 700, he became the bishop of the devices of Harran and proved to be one of the best bishops of his time. He also established a school at Habsnas. In 726 he attended the council of Manazgird.459 He died on the first of June, 734, which is also the day of his commemoration by the Church.

In addition to his asceticism, piety and godliness, he was a man of learning. He composed many polemical books, against the Malkite opponents.460 According to the patriarch Elias, he also wrote a treatise addressed to one of the Malkites, Constantine, Bishop of Harran.461 His biography was written by the monk Job of Manimim.